import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);

        write your code here......
        
        int single = 0,sum = 0;
        int count = 0;
        while(true){
            if((single = scan.nextInt())=0){
                count++;
                sum+=single;
            }
            else
            {
                break;
            }
        }
        double avg = sum1.0count;
        输出格式为：System.out.println(String.format(%.2f,avg));
        System.out.println(String.format(%.2f,avg));
        

    }
}